Boats of any appreciable size have bilges where any liquid introduced into the boat collects under the force of gravity. These liquids may, e.g., be fresh or sea water, oil or gasoline from the propulsion system or on-board machinery, etc. Solids may also find their way into the bilge. Such combinations of liquids and solids will be referred to herein as “bilge liquids”. The retention of bilge liquids on board a boat is highly undesirable, as it may contain hydrocarbons and/or other engine compartment liquids in addition to water.
There may be several bilges in a boat where bilge liquids may collect. Because they are in the very bottom of the boat, bilges are generally very difficult to access. and it generally is not practical to collect bilge liquids in a bucket or other container which may be carried through confined spaces and up ladders for disposal above deck. For this reason, bilge pumps are generally connected by flexible hose or rigid conduit to an overboard discharge. Bilge pumps typically are unable to distinguish between environmentally safe and unsafe liquids and the discharge thereof into the waterways creates additional problems.
In addition to the purging of bilge liquid from the bilges, there are spills of liquids of various types below decks, e.g. an oil leak in a piece of machinery, fuel leaks, or the accidental overturn of a coffee pot.
Finally, there are occasions when a boat may strike a submerged object or collide with another boat or a pier, breaching the hull to permit the introduction of water. To keep the boat afloat, it is highly desirable that the bilge pump be operable as a “crash” pump with a high pumping capacity and that it be substantially continuous in operation.
Commonly, bilge pumps comprise an electric motor driven, self-priming, pump, generally self actuating in responsive to a float switch to purge the bilge of bilge fluid. Such pumps are often mounted in the bilge areas, but they may also be located in a convenient space in the boat remote from the bilge, e.g., a below deck engine room or pump room where machinery is located. Such remote bilge pumps may be in communication with permanently installed bilge intakes in various of the bilges and with an overboard discharge conduit.
The liquid intake for the typical bilge pump is mounted proximate to the hull with a sensor, typically a float switch, which responds to the level of liquid in the bilge to turn the pump on and off. Such pumps, being positive displacement pumps and responsive to a predetermined liquid level, cannot completely drain the bilge. Moreover, the seals of the pump must be moistened to prevent excessive wear and replacement, a task often difficult in the confined space of a bilge or the engine room compartment of a boat.
Installation of bilge pumps is often difficult due to the tight quarters of the engine compartment or bilge area. Mounting the bilge pump to the hull, connecting the electrical wiring, and connecting the pump outlet to the drain conduit are all complicated by the confined working space. Replacing an inoperable bilge pump may even be more difficult. Replacement bilge pumps usually have a mounting footprint and overall configuration that is different from the original pump so that the wiring and drain conduits, designed to accommodate the original bilge pump, may not be compatible.
Vacuum systems are needed to completely remove bilge liquid from the bilges and/or to remove spills from other areas. It is known to provide a vacuum bilge system to supplement a conventional high volume liquid bilge pump. One such system is disclosed in the Baurley U.S. Pat. No. 6,837,174 wherein the residual bilge liquid is collected in a collection chamber under a negative pressure, and then discharged from the collection chamber under a positive pressure.
Others have attempted to address this problem in small boats by using small portable vacuum cleaners. Such portable vacuum cleaners are not connected to overboard discharges and generally have a very small storage capacity in a single chamber. This means that the operator must frequently stop the vacuuming process to manually take the collected liquid from the bilge or engine room on deck for disposal.
To the knowledge of applicant, applicant is the first to use a vacuum to collect bilge liquid into a container and to simultaneously use a centrifugal pump to discharge the bilge liquid from the container.
Large portable vacuum cleaners known as “shop-vacs” or “wet-vacs’ are known in non-marine environments, and are used for emptying spas or hot tubs. Typically, a single chamber is sealed by a top that has a vacuum pump depended therefrom so as to be located within the container. Air is pumped from the container through the top to create a negative pressure within the container, which is used to draw air and liquids into the container through a hose connected to the side wall of the container. A liquid pump located within the container is used to discharge liquid, typically through a garden hose.
There are a number of reasons why such “wet-vacs” are not suitable for use in marine environment, and particularly aboard a boat as a bilge pump. The use of a single chamber into which air and liquid is drawn and from which air and liquid is pumped gives rise to a number of problems. By way of example, the highly mixed air and liquid and the location of the air intake for the vacuum pump well down inside the chamber often results in liquid in the vacuum pump. In addition, the air in the air/liquid mixture within the chamber often results in an air lock of the liquid pump. These two problems become less severe as the chamber becomes larger, i.e., there is more space and hence more time for the liquid to separate from the air under the influence of gravity. Because the engine or pump rooms of a boat are accessible only through narrow passageways, typically down steps and around tight corners, large containers are not practical. Even if moved into an engine room in pieces and assembled there, there is insufficient room for the assembled vacuum cleaner.
Even if the liquid and vacuum pumps remain operational, the liquid level within the compartment must be carefully regulated—too much liquid increases the risk of liquid into the vacuum system and too little liquid dries the seals of the liquid pump. The liquid level control for such systems is generally a float switch, e.g., a caged ball at the mouth of the vacuum pump. Once the liquid in the chamber floats the ball into the mouth of the vacuum pump, the vacuum pump will hold it there effectively shutting down the introduction of fluid into the chamber until the vacuum pump is shut down permitting the caged ball to drop away from the vacuum pump. Such systems typically require constant operator attention, generally unavailable on a boat.
There is thus a long felt need to provide a bilge pump sufficiently small for use in the confined spaces aboard a boat that is portable, or at least easily installed and removable for replacement, that is capable of removing essentially all liquid from the bilge.
In one aspect, the bilge pump of the present invention utilizes two chambers, and the physical configuration of those chambers, to effect separation of air from the bilge liquid.
In another aspect, the bilge pump of the present invention provides independent control of both bilge liquid intake and bilge liquid discharge to insure optimization of bilge liquid throughput. These controls are also utilized to prevent both vapor lock of the liquid pump the receipt of bilge liquid into the vacuum pump.
In a further aspect, the bilge pump of the present invention provides for both the complete draining of the chamber and for the utilization of the bilge pump as a high volume crash pump or fire extinguisher.
In yet a further aspect, the bilge pump of the present invention can selectively discharge the bilge liquid into a container in the case of hydrocarbons or overboard in the case of environmentally safe liquids.
In yet another aspect, the chambers of the bilge pump of the present invention are easily accessible and liquid can be poured into the top of the input chamber when the pump is used as a transfer pump; the basket filter may easily be removed for cleaning through the same opening; and the liquid pump may easily be removed for service or replacement from the bottom of the output chamber.
In yet another aspect, the bilge pump of the present invention may be used to selectively pump the liquid on which the boat floats as a fire extinguisher.
These and many other objects and advantages of the bilge pump of the present invention will be apparent to one of skill in marine bilge pumps from a review of the following drawings and detailed description of a preferred embodiment.